I have put out my pea, mangetout, Raddish, Lettuces and rocket. I've put fleece tunnel cloches over most of these to protect them from waterlogging - will that work?
Over the bank holiday weekend I lifted up the fleece over the 1st early potatoes to get to the row to earth them up against what sounded like a forecast for bad frost and the soil was actually more wet than the other potato beds that had been open to the sun and wind. I think when the soil is already saturated, the fleece doesn't make any difference but does stop the moisture from escaping during dry days.
Also will the cloches keep those seeds protected from pests?
if pests are already inside the cloche when it was erected such as slugs and snails which love all those you sowed, then no but may protect from invading pests.
Other seeds I am yet to put in the ground are sweet corn, cabbage, calabrase, my various beans, carrots, parsnips, celery, and courgette. I know I need to put netting around the calabrase and cabbage. Should I consider protection for any of the other crops too?
Carrots would benefit as the biggest problem is from the carrot fly which lay eggs and the larvae tunnel in the root. A very fine mesh is needed. Parsnips are supposed to be susceptible to the carrot fly but touch wood, I've never had problems.
Cabbage & calabrese - definitely against the cabbage white butterfly from laying eggs. The caterpillars do a lot of damage in a very short space of time. Do not underestimate the cabbage white butterfly - they can squeeze through the tiniest gap (the one you missed but they seem to find), and if leaves are close to or touching the net, they can still lay their eggs on them. The netting needs to have a small mesh. Slugs and snails can be a problem to young plants. Also, consider collars to fit round the base of the plants to deter cabbage root fly.
Sweetcorn - they need protection from the risk of frost and cold and from slugs/snails when young, but once they start growing in earnest, none is needed. They do need to be planted in a block formation to improve pollination by wind.
Courgettes and beans - again, protect from frost and more importantly, from slugs and snails until they get established. Once they get growing, they'll be fine, and you'll not get a good crop of courgettes if the bees and other pollinating insects can't visit
Celery - I don't recall problems from pests, maybe from slugs and snails especially when young but thereafter seemed pest free